Ford Tests Natural Gas In Crown Victoria

Battery-powered electric cars hold the promise that someday you will be able to walk out your front door, take a deep breath and inhale clean air - without having to put on a gas mask.

But while offering the hope of clean air, battery-powered cars don't promise utopia. Perhaps they won't emit gunk into the atmosphere, but after only about 60 to 100 miles of travel, they have to be pulled over to an electrical socket, plugged in and kept motionless for six to eight hours while absorbing a fresh supply of juice.

In a mobile society, immobility after 100 miles is more difficult to swallow than a mouthful of particulates left behind by a petroleum-burning vehicle.

Enter another alternative fuel - natural gas.

You can heat, cool and cook with it - just like electricity. So why not run your car, truck, utility vehicle or van with it?

Natural gas is not only plentiful in the United States, it is also cheap. And although batteries are emission-free, natural gas claims lower hydrocarbon and carbon monoxide levels and about a 70 percent reduction in smog-forming potential than gasoline. So although a natural-gas car is not as clean as an electric, it is cleaner than a gasoline-burning car.

The natural gas folks, like the electric power folks, would have you believe that their product not only will clear the air but will erase the budget deficit, eliminate famine and pestilence and take our minds off the fact that Cheers has gone off the air.

To prove it, they made available a 1992 Ford Crown Victoria converted to natural gas power, one of 50 built by Ford with $50 million in seed money planted by the Gas Research Institute, the Chicago-based research and development arm of the natural gas industry. Those 50 cars will undergo three years of real-world testing by utilities.

I last drove a natural-gas-powered car more than 10 years ago. It was a hybrid, meaning the car ran on gasoline or natural gas at the flip of a switch. The engine idled roughly and there was a pronounced lag time between stepping on the pedal and the engine coming to life. And because the car had a gasoline tank, the natural gas tanks had to be put in the trunk, eliminating storage space.

So although I didn't expect much from the Crown Vic, I was pleasantly surprised. Slip behind the wheel and turn on the key and you couldn't tell whether gasoline or natural gas was providing the power. The only notable difference was a muffled tap-tap-tap coming from under the hood, which was the sound of the fuel injectors opening and closing.

The tapping can be heard because liquid gas muffles the sound from the injectors and natural gas vapor doesn't, said Keith Davidson, director of power generation and transportation systems for the GRI.

The same 4.6-liter, 190-horsepower V-8 that powers the gasoline-burning Crown Vic was modified to accept compressed natural gas, or CNG. Modification entailed adding larger injectors to accommodate natural gas vapor rather than gasoline liquid. The engine's compression ratio also had to be raised because the higher-octane natural gas (140 vs. 87 to 91 on gasoline) burns slower.

The Crown Vic idled smoothly and accelerated without lag time or hesitation. Pass, merge, climb the hill. Anything gasoline could do, natural gas could do as well.

We didn't have a chance to test the engine in subzero weather, of course. Water in the fuel can crystallize and cause cold-start problems, according to Phil Smith, project leader-natural gas for Ford Motor Co. who oversees the Crown Vic testing.

''In cold weather you could get rough idle and stumble from the ice crystals, and we need to find ways to get more heat to the fuel in the warm-up cycle,'' Smith said.

The Crown Vic's size points to a big plus for natural gas. Battery cars are clean and, without an engine, they're very quiet, but most proposed battery vehicles are two-seaters.

The bigger and heavier the vehicle, the shorter the driving range. And because the 32 batteries needed to propel a vehicle take up so much room, even a minivanbecomes a two-seater.

With a natural-gas-powered car like the full-size Crown Vic, you still can hold five adults and their luggage. That's because the four natural-gas tanks are in the dead space between the rear seat and trunk as well as under the car, where the gasoline tank would be. A big benefit.

Availability, low cost of natural gas a plus

Natural gas is plentiful - and cheap. The pump price was only 97.9 cents a gallon at a station in the city, where taxes probably add a dime to what the suburban price would be.

But the natural Crown Vic averages 13 miles per gallon in city/ highway driving combined (the gasoline version averages 18 mpg city/26 mpg highway), and that means the combined 10 gallons of fuel in the four tanks gives you a 130-mile range before they need to be refilled. That's only slightly more range than a battery-powered car would have. Why not add more tanks to increase range? Smith says more tanks add weight, which would offset any gains.